1. Field of the Invention
The present invention relates to a socket for an electrical part for detachably holding the electrical part such as semiconductor device (called xe2x80x9cIC packagexe2x80x9d hereinlater), and more particularly, a socket for an electrical part including an improved structure of a contact pin to be electrically connected to a terminal of the electrical part and capable of finely positioning the terminal and smoothly mounting the electrical part to a socket body.

2. Prior Art of the Invention
As such a xe2x80x9csocket for electrical partsxe2x80x9d, there is known an IC socket for detachably holding an IC package as an xe2x80x9celectrical partxe2x80x9d. In such socket, the IC package is accommodated in a socket body, each of contact pins is arranged so as to contact, at two points, upper and lower surfaces of each of terminals of the IC package, and when an operation member is operated, an upper elastic piece of the contact pin is elastically deformed so that an upper contact portion of the upper elastic piece is contacted to or separated from the upper surface of the terminal of the IC package.
However, in such conventional two-point-contact structure, a lower contact portion of the elastic piece contacting the lower surface of the terminal is constructed to be stationary (fixed), and only the upper contact portion thereof is constructed to be deformable. Because of such structure, although a wiping effect can be achieved at the upper contact portion, the wiping effect cannot be achieved at the lower contact portion. Thus, the contact stability between the terminal of the IC package and the lower contact portion is not so good.
Furthermore, in such conventional two-point-contact structure, the terminal of the IC package is clamped between the lower and upper contact portions and the height (level) of the terminal is determined in a state that the upper and lower elastic pieces are balanced in force. Accordingly, there is a fear that the heights of the respective terminals are not uniform and, hence, the terminals are undesirably deformable. There is also a fear that contact pressures between the respective contact portions and the terminals differ and, hence, the good contact stability cannot be achieved.
Still furthermore, in such conventional two-point-contact structure, as shown in FIG. 14, lower contact portions 2a of the respective contact pin 2 project upward, and as shown with two-dot-chain line, when the IC package 3 is inserted in an inclined fashion, terminals 3a of the IC package 3 are inserted between the adjacent two lower contact portions 2a, which may result in an defective sitting or mounting thereof, thus being inconvenient.
A primary object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art mentioned above and to provide s socket for electrical parts capable of achieving a desired wiping effect at a lower contact portion of a contact pin to thereby improve stability in the contacting state thereof.
Another object of the present invention is to provide a socket for electrical parts capable of accurately positioning a terminal of an electrical part to thereby prevent deformation of the terminal and improve the contacting stability thereof.
A further object of the present invention is to provide a socket for electrical parts capable of preventing undesired seating of the terminal at the time of mounting the electrical part to a socket body to thereby prevent defective seating or mounting of the terminal.
These and other objects can be achieved according to the present invention by providing, in one aspect, a socket for an electrical part adapted to be electrically connected to a terminal of an electrical part, comprising:
a socket body;
upper and lower contact pins mounted to the socket body so as to be contacted to and separated from the terminal of the electrical part, the upper contact pin being formed with an upper elastic piece having an upper contact portion contacting an upper surface of the terminal and the lower contact pin being formed with a lower elastic piece having a lower contact portion contacting a lower surface of the terminal; and
an operation member disposed to the socket body to be vertically reciprocally movable with respect to the socket body, in which when the operation member is reciprocally moved, the upper elastic piece is elastically deformed to thereby displace the upper contact portion so as to be contacted to and separated from the upper surface of the terminal,
wherein when the upper contact portion is contacted to the upper surface of the terminal of the electrical part so as to clamp the terminal between the upper and lower contact portions, the lower elastic piece is elastically deformed by an elastic force of the upper elastic piece to thereby displace the lower contact portion so that the terminal of the electrical part and the lower contact portion are slidably moved.
In a preferred embodiment of this aspect, when the upper contact portion contacts the upper surface of the terminal so as to clamp the terminal between the upper and lower contact portions, the lower elastic piece is elastically deformed by the elastic force of the upper elastic piece and the lower contact portion is displaced in a direction reverse to the displacing direction of the upper contact portion so that the terminal of the electrical part and the lower contact portion are slidably moved.
In another example, when the upper contact portion contacts the upper surface of the terminal so as to clamp the terminal between the upper and lower contact portions, the lower elastic piece is elastically deformed by the elastic force of the upper elastic piece and the lower contact portion is displaced in a same direction as the displacing direction of the upper contact portion so that the terminal of the electrical part and the lower contact portion are slidably moved.
The upper contact pin and the lower contact pin are formed integrally as one member.
According to the structure of the present invention of this aspect, the lower elastic piece is elastically deformed by using the elastic force of the upper elastic piece to thereby slide the lower contact portion on the lower surface of the terminal. Thus, the wiping effect can be achieved even by the lower contact portion to thereby improve the stability in contact.
In the embodiment in which the lower contact portion is displaced in a direction reverse to the displacing direction of the upper contact portion, a force from both the contact portions acting to the terminal of the electrical part can be cancelled each other, thus preventing the terminal from being deformed.
In another aspect of the present invention, there is also provided a socket for an electrical part adapted to be electrically connected to a terminal of an electrical part, comprising:
a socket body;
upper and lower contact pins mounted to the socket body so as to be contacted to and separated from the terminal of the electrical part, the upper contact pin being formed with an upper elastic piece having an upper contact portion contacting an upper surface of the terminal and the lower contact pin being formed with a lower elastic piece having a lower contact portion contacting a lower surface of the terminal;
an operation member disposed to the socket body to be vertically reciprocally movable with respect to the socket body, in which when the operation member is reciprocally moved, the upper elastic piece is elastically deformed to thereby displace the upper contact portion so as to be contacted to and separated from the upper surface of the terminal; and
a positioning means for stopping the terminal of the electrical part to a predetermined position when the terminal of the electrical part is depressed by the upper contact portion.
In a preferred embodiment of this aspect, the socket body is provided with a partition wall section formed with a plurality of slits to which the lower contact portions of the lower contact pins are inserted to be movable, the slit having a width smaller than a width of the terminal and when the terminal is depressed by the upper contact portion of the upper contact pin, the positioning means operates to stop the terminal to the predetermined position by abutting the lower surface of the terminal against an upper surface of the partition wall section.
When the upper contact portion is contacted to the upper surface of the terminal of the electrical part so as to clamp the terminal between the upper and lower contact portions, the lower elastic piece is elastically deformed by an elastic force of the upper elastic piece to thereby displace the lower contact portion so that the terminal of the electrical part and the lower contact portion are slidably moved.
The upper contact pin and the lower contact pin are formed integrally as one member.
According to this aspect, the terminal of the electrical part is moved downward with being clamped between the upper and lower contact portions and are then positioned at a predetermined level by the positioning means, so that the deformation of the respective terminals can be prevented and the stable contacting state between the contact pins and the terminals can be ensured.
In the arrangement of the partition wall section formed with the slits, the terminals are stopped and positioned to the predetermined positions by narrowing the width of the slit than the width of the terminal, so that the deformation of the respective terminals can be prevented and the stable contacting state between the contact pins and the terminals can be ensured.
Furthermore, since the lower elastic piece is elastically deformed by using the elastic force of the upper elastic piece to thereby slide the lower contact portion on the lower surface of the terminal, the wiping effect can be achieved even by the lower contact portion to thereby improve the stability in the contacting state.
In a further aspect of the present invention, there is provided a socket for an electrical part adapted to be electrically connected to a terminal of an electrical part, comprising:
a socket body;
upper and lower contact pins mounted to the socket body so as to be contacted to and separated from the terminal of the electrical part, the upper contact pin being formed with an upper elastic piece having an upper contact portion contacting an upper surface of the terminal and the lower contact pin being formed with a lower elastic piece having a lower contact portion contacting a lower surface of the terminal; and
an operation member disposed to the socket body to be vertically reciprocally movable with respect to the socket body, in which when the operation member is reciprocally moved, the upper elastic piece is elastically deformed to thereby displace the upper contact portion so as to be contacted to and separated from the upper surface of the terminal,
wherein the socket body is provided with a partition wall section formed with a plurality of slits into each of which at least a portion of the lower contact pin is inserted and the partition wall section is provided with a protruded portion projecting over a level of an upper surface of the lower contact portion of the lower contact pin.
In a preferred embodiment of this aspect, a plurality of upper and lower contact pins are arranged and the protruded portion is formed to a portion of the partition wall section between one lower contact pin disposed endmost position and another one lower contact pin disposed adjacent thereto.
The protruded portion has a top surface portion formed to provide a round (R) shape.
When the upper contact portion is contacted to the upper surface of the terminal of the electrical part so as to clamp the terminal between the upper and lower contact portions, the lower elastic piece is elastically deformed by an elastic force of the upper elastic piece to thereby displace the lower contact portion so that the terminal of the electrical part and the lower contact portion are slidably moved.
The upper contact pin and the lower contact pin are formed integrally as one member.
According to this aspect, since the socket body is provided with the partition wall section formed with a plurality of slits into each of which at least a portion of the lower contact pin is inserted and the partition wall section is provided with the protruded portion projecting over a level of an upper surface of the lower contact portion of the lower contact pin, even if the electrical part is inserted in an oblique fashion, the terminal is guided by the upper surface portion of the protruded portion and corrected in its attitude to a normal attitude and then guided to the predetermined position on the lower contact portion. Thus, the terminal is not guided between adjacent two lower contact portions and the defective seating or mounting can be prevented.
In the arrangement that the protruded portion is formed to a portion of the partition wall section between one lower contact pin disposed endmost position and another one lower contact pin disposed adjacent thereto, the defective mounting of the electrical part can be further prevented.
By forming the top surface portion of the protruded portion so as to provide a round (R) shape, the terminal of the electrical part can be smoothly guided thereon.
The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings.